Google continued to shrink its carbon footprint in 2012, according to new data that shows the average Google user pumps out the same amount of carbon emissions each month as they would driving a car one mile.
The search giant yesterday confirmed that last year it emitted 30.3 metric tons of carbon per million dollars of revenue, compared to 44.3 tons of CO2 per $1 million in 2011 -- representing a significant 32 percent reduction in carbon intensity.
The company has calculated that its average "active user" does 25 searches and watches 60 minutes of YouTube per day, while also operating a Gmail account and using some of the search giant's other services, resulting in a daily carbon footprint of 8 grams of CO2 a day.
The sharp decline in the company's overall emissions was attributed to the inclusion of green power purchase agreements (PPAs) in its carbon footprint calculations for the first time, as required by the Carbon Disclosure Project methodology it used to measure its footprint.
During the last year, Google has also made a series of investments in renewable energy projects, including $12 million in a 94 MW solar array in South Africa in May, and $200 million in a 161 MW wind farm in Texas.
The latest update confirms that the change in reporting methodology meant that total emissions fell nine percent last year to 1.5 million tons of CO2.
It also reveals that without the PPAs taken into account, energy efficiency improvements mean its carbon intensity would still have fallen, albeit by a more modest 4 tons of CO2/$1.6 million to 40.3 t CO2/$1.6 million.
"For the fourth year in a row, we're emitting less carbon per million dollars of revenue," Jolanka Nickerman, Google's program manager for carbon offsets, wrote in a blog post. "This means that our footprint is growing more slowly than our business because we're able to get more done with each gram of carbon we emit."
As Nickerman acknowledges, the performance does mean that the company's total carbon footprint continued to rise on a like-for-like basis as its enjoyed strong revenue growth.
But she added that last year saw Google become "carbon neutral" for the sixth year in a row when taking into account the offsets it purchased to cover its total 1.5 million tons of CO2 emissions.
To learn more, Google's VP of data centers, Joe Kava, will speak at VERGE SF October 14-17.